1. Field of the Invention
The present invention is directed to a system and method for generating plasma discharge and, in particular, to a slot discharge, non-thermal plasma process and apparatus the produces a higher volume of plasma.
2. Description of Related Art
A “plasma” is a partially ionized gas composed of ions, electrons, and neutral species. This state of matter is produced by relatively high temperatures or relatively strong electric fields either constant (DC) or time varying (e.g., RF or microwave) electromagnetic fields. A plasma discharge is produced when free electrons are energized by electric fields in a background of neutral atoms/molecules. These electrons cause electron atom/molecule collisions which transfer energy to the atoms/molecules and form a variety of species which may include photons, metastables, atomic excited states, free radicals, molecular fragments, monomers, electrons, and ions. The neutral gas becomes partially or fully ionized and is able to conduct currents. The plasma species are chemically active and/or can physically modify the surface of materials and may therefore serve to form new chemical compounds and/or modify existing compounds. Discharge plasmas can also produce useful amounts of optical radiation to be used for lighting. Numerous other uses for plasma discharge are available.
U.S. Pat. Nos. 5,872,426; 6,005,349; and 6,147,452, each of which is herein incorporated by reference in their entirety, describe a glow plasma discharge device for stabilizing glow plasma discharges by suppressing the transition from glow-to-arc. A dielectric plate having an upper surface and a lower surface and a plurality of holes extending therethrough is positioned over a cathode plate and held in place by a collar. Each hole in the dielectric acts as a separate active current limiting micro-channel that prevents the overall current density from increasing above the threshold for the glow-to-arc transition. The use of capillaries in a cathode plate while successful in limiting the current in order to suppress the glow-to-arc transition also limits the amount of plasma produced. To increase the amount of plasma produced we need to increase the percentage of overall cathode area that the current limiting system occupies.
It is therefore desirable to develop a device that solves the aforementioned problem while generating a relatively large volume of non-thermal plasma.